Tropical coastal waters remain uncharacterized with regard to conditions, which are responsible for higher transmission of diseases in the use of these waters. Uncontrolled urbanization leading to coastal water pollution is one problem. Another problem is the reliance on hygienic, bacterial water quality guidelines developed for temperate countries, which are not applicable to tropical countries because the fates of microorganisms are controlled by their environment. In tropical regions, climatic conditions allow microorganisms to interact with humans and the environment throughout the year, even allowing some pathogens to grow and possibly gain virulence genes. A major gap is in understanding the causal link between disease transmission during the use of coastal waters and the ecological processes at the terrestrial-marine interface that control the kinds and concentrations of pathogens in tropical coastal waters. The central hypothesis is that the tropical ecosystem represents a distinct environment, which differs significantly from the temperate ecosystem and as a result, the strategy for water quality management in the tropics can be expected to differ. The long-term goal of this project is to obtain reliable data on tropical coastal water so effective guidelines aimed at improving the health of humans living in tropical ecosystems can be developed. To attain this long-term goal and to address the central hypothesis, this project will address the following three aims: 1) Determine the sources, survival and ecology of indicators of pathogens and pathogens in sediments, marine foods and water in tropical coastal waters. 2) Evaluate the use of indigenous mollusks to concentrate pathogens from tropical waters and the use of culture and molecular methods to measure their presence. 3) Assess the prevalence of virulence genes within the meta-genome of coastal microbial communities.